At the moments when spring and autumn begin, the sun is directly over the equator.
Days become shorter from the Summer Solstice in June [the longest day of the year] through the Winter Solstice in December [the shortest day of the year] , when the days begin growing longer again. [At the Vernal and Autumnal Equinoxes, midway between the solstices, the days and nights are of equal lengths.]
Equinoxes
In the tropics. The sun is straight overhead at some time or other, between the tropic of Cancer, in the north and the tropic of Capricorn. During the equinoxes (vernal and autumnal), the sun is directly overhead at the equator.
The vernal equinox occurs in March and marks the start of spring in the Northern Hemisphere, while the autumnal equinox occurs in September and marks the start of fall. During these equinoxes, day and night are approximately equal in length all over the world.
The relationship between velocity and the derivative of position is that velocity is the derivative of position with respect to time. In other words, velocity is the rate of change of position over time.
yes
The Autumnal Equinox occurs in September when the length of day and night is nearly equal. This is when the sun shines directly on the equator. People often have equinox parties to celebrate this date.
The two equinoxes.
The derivative of position is velocity. This means that velocity is the rate of change of position over time.
Pretty much, yes. You have the spring (vernal) and autumn (autumnal) equinoxes, so it's around that time. Midsummer's day is around the first day of summer. But the equinoxes aren't precisely (to the smallest fraction of a second) halfway between, because the velocity of earth's orbit is constantly changing throughout the year.
The equinoxes and solstices are the first days of seasons. On the equinoxes, night and day is the same length. On the solstices, the day is either the longest or the shortest day of the year, depending on which solstice it is and which hemisphere you are in,
equinoxes